Rub the jerk sauce evenly over the outside and inside of the turkey. Place the turkey breast-side down in a 2-gallon heavy-duty resealable plastic bag. Squeeze out as much air as possible and seal the bag. Refrigerate and marinate for 24 to 48 hours, turning occasionally.
Position the oven rack near the bottom of the oven and preheat to 350˚ F. Remove the turkey from the plastic bag. Wipe off the jerk sauce inside and out, pat the turkey dry, and season generously inside and out with salt and pepper. Loosely pack the Cornbread-Andouille Dressing into the cavity. Pull back the skin over the breast and rub some butter under the skin. Rub the outside of the turkey with more butter, and sprinkle with salt and pepper. Truss the turkey if desired, and place breast-side up in a large roasting pan at least 2 inches deep.
Lower the oven temperature to 325˚ F and roast the turkey, basting frequently with the pan juices, until a meat thermometer registers 165˚ F, 3 to 3 1/2 hours; when the skin is golden brown, cover with foil to prevent over-browning. Remove the turkey from the oven and put it on a warmed platter. Cover loosely and let rest for 30 minutes before carving.
In a large skillet, melt the butter over medium heat, then add the sausage and cook about 2 minutes. Add the onion, celery and bell pepper and saute until the vegetables are tender but not browned, about 2 minutes. Remove from the heat and cool for 5 minutes.
In a large bowl, combine the cornbread cubes, poultry seasoning, thyme and salt and pepper. Stir in the cooled sausage mixture and egg.
Add the stock, a little at a time or as needed, until the mixture becomes moist but not wet. Cover with plastic wrap and refrigerate until ready to use.
Instead of jerk sauce, you can use salt-free Jamaican jerk dry spice blend. Rub the turkey with vegetable oil, then sprinkle the dry spice evenly over and inside the turkey.